Cognitive decline is a natural consequence of free-radical damage, together with long term suboptimal nutrition, and lifestyle factors, including stress. While memory loss is common in the aging population and a certain amount is expected to accompany the process of growing older, today, cognitive decline is increasingly experienced in mid-life, and over time can lead to reduced memory, concentration, and verbal ability. Furthermore, cognitive impairment is not limited only to the middle aged and elderly; studies are showing a growing number of children across the world are experiencing troubles in the classroom, and struggle with focus and attention span, problems which affect their ability to learn and also have implications for future success.
One of the natural supplements that has been studied extensively for its role in various aspects of cognitive support is L-theanine. L-Theanine is an amino acid primarily found in tea. Discovered as a constituent of green tea in 1949, the nutrient was approved in Japan in 1964 for use in all foods, including chocolates, soft drinks, and herb teas. Research has found that theanine is able to cross the blood–brain barrier, and impart its psychoactive properties; it has been studied for its potential ability to reduce mental and physical stress, improve cognition and improve in a synergy with caffeine. Theanine has also been shown to have a protective effect on the brain and prevent neuronal cell death after certain types of stroke. Furthermore, theanine has been found to help boost immune function and reduce anxiety-induced hypertension.
Cognitive support, memory and attention
Theanine in tea has been shown to be associated with improved long term cognitive outcomes. In one study, elderly volunteers who ingested green tea powder with a high theanine concentration showed significantly lower decline in cognitive function compared a placebo group (Kakuda et al 2011). A combination of green tea extract and L-theanine has also been shown to improve memory and attention span in subjects with mild cognitive impairment in another double-blind placebo-controlled study with brain theta waves (a sign of cognitive alertness), increased significantly in 4 areas of the brain after 3 hours (Park et al 2011).
Another placebo controlled study on Theanine done in 2008 compared the effect of 50 mg caffeine, with and without 100 mg of L-theanine, on cognition and mood in volunteers as well as word recognition, rapid visual information processing, and attention switching. The combination of L-theanine and caffeine combination improved both speed and accuracy of performance of the attention-switching task at 60 min, and reduced susceptibility to distracting information in the memory task at both 60 min and 90 min suggesting the added benefits of caffeine taken with L-theanine.
Studies of theanine in children has also been found to be useful for ADHD, through its facilitation of improved sleep. In a randomized double blind controlled trial of 98 boys, 400 mg of theanine daily was found to be safe and effective in improving quality of sleep and was recommended as an adjunct supplement therapy for ADHD (Lyon et al 2011).
Kakuda T. Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction.
Pharmacol Res. 2011 Aug;64(2):162-8. doi: 10.1016/j.phrs.2011.03.010. Epub 2011 Apr 6.
Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. 2011 Dec;16(4):348-54.
Park SK, Jung IC, Lee WK, Lee YS, Park HK, Go HJ, Kim K, Lim NK, Hong JT, Ly SY, Rho SS. A combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study. J Med Food. 2011 Apr;14(4):334-43. doi: 10.1089/jmf.2009.1374. Epub 2011 Feb 8.